A conventional mirror finishing machine is a super-finishing machine which employs a crank-slider mechanism as a motion mechanism. The motion mechanism of the super-finishing machine is schematically shown in FIG. 1, and includes a spring 10, an abrasive stone 12, an eccentric rod 13, a connecting rod 14, and a slider 15. The eccentric rod 13 is engaged with the connecting rod 14 which is further connected to the slider 15. The abrasive stone 12 is mounted on the slider 15, and sustains against a work piece (not shown) owing to the elastic force of the spring 10. During the operation, a motor (not shown) drives the eccentric rod 13 of a certain eccentricity (e), as indicated by a circular track arrow, so as to further transmit the slider 15 through the connecting rod 14 to have a reciprocating motion. Accordingly, the abrasive stone 12 mounted on the slider 15 synchronously reciprocates and grinds the surface of the work piece to a mirror level, i.e. a roughness of 0.1.about.0.5 .mu.m maximal height.
For the conventional super-finishing machine, the stroke of the reciprocation of the slider, and the abrasive stone, is generally equal to the revolving diameter of the crank, i.e. 2e, which is as small as a couple of millimeters. Furthermore, the reciprocating motion is confined to a small specific area. Consequently, the super-finishing machine has to be mounted on an work stand of another machine so that the abrasive stone can travel farther by way of a screw rod of the additional work stand.
Several further designs for micron-level feeding and precise positioning have been developed. For example, Y. Furukawa et al. designed a micro cutting machine which performs micron-level feeding by way of friction drive (Annals of the CIRP, Vol. 35/1/1986, p. 279-282); M. Yamaguchi et al. developed a precise feed mechanism combining friction drive with an air slider and applied to an ultra precision lathe (J. JSPE, Vol. 56, 1990, p. 146-151); and M. Takahashi et al. developed an experimental apparatus which performs precise positioning by way of friction drive (J. JSPE, Vol. 57, 1991, p. 102-107). In addition, various ultra precision machines have been developed, and even marketed, by Lawrence Livermore Laboratory (U.S.A.) and Euro Precision Technology company (Japan).
The friction drive for the feeding and/or positioning mechanism of the aforementioned designs, however, is driven by a servo motor in a single direction so as not to be very suitable for a mirror finishing machine.